Authentication Cryptography Plaintext Encryption Algorithm Key Ciphertext

Authentication

Cryptography Plaintext Encryption Algorithm Key Ciphertext

Decryption Ciphertext Decryption Algorithm Key Plaintext

Kerckhoff’s principle

Decryption Device

Two Definitions

Function Random input

Birthday Bound

Encryption Algorithm Plaintext Collisions in the output?

m H(m) h

Variable Length Messag e Hashing Algorithm Fixed Length Digest

Uses of Hash Functions

A Cryptographic Hash function

Definitions

Symmetric Key Encryption Message by sender Message at receiver Prkey Pr-key Receiver-end Encrypted Message Internet Encrypted Message

Others contribute

The P-K systems

Patents

Diffie-Hellman algorithm

Diffie-Hellman algorithm

A B’s public Encrypted Message key Internet Message B’s private Encrypted Message key B

Public Key of Alice

Certifying Authorities

Digital Certificate

Digital signatures Ms g Digest Algorithm Encoding using Private key of A Digest Ms g Digest Algorithm Digest

Secure Socket Layer

Pretty Good Privacy

Message/data Encryption Combines conventional and public-key encryption

Message/data Encryption Combines conventional and public-key encryption

Message Authentication Codes

MAC’s for integrity

Function for MAC

Authentication issues

International Laws

Difference between SCTP and TCP

Uses of SIP

Session Initiation Protocol

H. 323 and H. 248

H. 248/MEGACO

IEEE 802. 3 Standard 8 6 6 2 46 B – 1500 B bits 368 -12, 000 FRAME CRC – Cyclic Redundancy Check 4